In the field of diagnostic monitoring of operating parameters within reciprocating gas compressor cylinders, it is known that if excess liquids accumulate within the piston compression chamber, the additional volume and density of liquids increases pressures and temperatures within the compression chamber with resulting increased compression and tension on the piston rod and potential self-destruction of the piston rod and piston head. It is a preference in the industry for real-time diagnostic monitoring of operating parameters so that at the initial deterioration of parameters within piston chambers, the reciprocating gas compressor pistons can be stopped before irreparable damage occurs to the cylinders, piston heads or piston rods.
Typical of the prior art are those monitoring devices disclosed in the following U.S. Patents. In U.S. Pat. No. 5,471,400, to Smalley et al., a method for detecting reciprocating compressor cylinder leaks is disclosed, the method including utilizing a computer-based control means, sensing the pressure within the operating cylinder at predetermined intervals of cylinder volume, calculating sensed pressure versus volume curves for the operating cylinder, and comparing sensed pressure versus volume curves with an ideal calculated pressure versus volume curves for a computer generated model of an ideal, non-leaking cylinder having dimensions of bore and stroke of similar size and operation as the monitored cylinder. Sensed parameters are analyzed in conjunction with ideal calculated parameters for each successive interval of crankshaft rotation. The analyzing steps include determining a course of remedial repairs to be performed on the cylinder based on probable leaks in the cylinder. Real-time modifications in the operation of the monitored cylinder are not included in the method. The method of detecting leaks does not measure or calculate the actual amount of gas entering and exiting the cylinder, nor are the entering and exiting gas amounts ratioed. The method also does not accomplish continuous monitoring for one cylinder, nor does the method simultaneous sample a plurality of diagnostic parameters from multiple cylinders, for remote real-time analyses by computers and monitoring of analyses by operators to allow for timely control of the monitored reciprocating compressor cylinders. Real-time control of compressor cylinders operating parameters is preferred to protect cylinders from self-destruction due to excess compression and tensions imposed on piston heads and piston rods due to the presence of excess temperatures or pressures created by dense liquids or gases within the cylinders.
In U.S. Pat. No. 4,456,963, to Wiggins, an apparatus and method for measuring and displaying performance characteristics of a reciprocating piston machine is disclosed, including means for providing data for crank-shaft angular position and angular velocity, means for providing data for cylinder pressure within the piston machine, and means for calculating horsepower. The means for providing data includes a pressure transducer, such as a strain gauge type of transducer, coupled to the reciprocating piston machine, and a crank angle or shaft encoder assembly for measuring crankshaft angle and piston position related events in the piston machine. A central processing unit actuated by an operator, receives data acquired by the pressure transducer and the shaft encoder assembly upon signal by an operator, with analysis by a connectable analyzer after an operator completes the hookup of the analyzer to the engine compressor. The apparatus and method of measuring requires input of information by an operator via a keyboard assembly to initialize the analyzer, with retrieval of parameters monitored by the transducers when requested by an operator. The apparatus and method of measuring allows calculation of horsepower for the tested piston and cylinder as a snapshot analysis of conditions monitored at a selected time sequence of the piston machine operation, and does not provide continuous reporting of temperatures, pressures, and volumes for one or more reciprocating compressor cylinders. The apparatus and method for measuring requires a display device such as an oscilloscope or a computer screen to view the calculated horsepower, with additional analyses attempted upon prompting by an operator via a keyboard assembly, therefore the measuring and analyses are not continuous during the operation of the piston and cylinder. Thus, if a disrupting amount of liquid enters the cylinder chamber while the transducers and analyzer are not connected or are not requested by an operator, the cylinder can self-destruct before analysis is completed by the apparatus and method of measuring.
In U.S. Pat. No. 4,783,990, to Eberle, et al., an apparatus for measuring the quantity of gas pumped by a compressor is disclosed, the apparatus including pressure sensors for measuring the external suction and external discharge gas pressures of the compressor, and a data storage means for storing data representative of the piston displacement and piston clearance. The apparatus for measuring can also include a temperature sensor means for detecting the temperature of the gas at entry and exit points in the compressor for calculating the gas throughput. A data storage means can be connected to the compressor for eventual down-loading of data by an operator when requested by an operator either by connection of the data storage means to a computer, or by remote transmission to a central storage computer. The apparatus for measuring allows calculation of the throughput of the gas, by comparison of the monitored pressures and temperatures to the manufacturer's previously calculated load curves for an ideal "as-built" piston and cylinder configuration. The apparatus for measuring does not provide for real-time measurements and reporting of pressures and temperatures for a piston and cylinder as modified by valve leaks or bore/stroke changes. The apparatus for measuring does not provide real-time calculations of compressor cylinder gas or liquid volumes, for one or a series of reciprocating compressor cylinders, without an operator's assistance. Therefore, if a disrupting amount of liquid enters one cylinder of a multi-cylinder compressor, while the pressure sensors and data storage means of the apparatus for measuring are not operating, the cylinder can self-destruct before sampling and analysis is completed and reported to an operator by the apparatus for measuring.
Therefore, it is an object of the present invention to provide a method for continuous diagnostic monitoring of operating parameters sampled within a compressor cylinder.
It is another object of the present invention to provide a monitoring apparatus for continuous diagnostic monitoring and analysis of multiple operating parameters sampled within a compressor cylinder, with timely reporting of non-specification monitored parameters.
It is another object of the present invention to provide a monitoring apparatus for continuous diagnostic monitoring and analyses of multiple operating parameters sampled within a plurality of compressor cylinders.
It is another object of the present invention to provide a method of continuous monitoring and analysis of a plurality of operating parameters within a plurality of compressor cylinders operating in concert, with timely reporting of analyzed parameters to a remote central control computer for timely display and reporting to operators of non-specification monitored parameters.